Last year, Ford launched the new Focus RS and everyone was bouncing up and down in delight at how brilliant it was. Since then, people have done way too much thinking and ended up finding reasons to come over all sniffy about it, but let’s not be sad sacks. This is a sensational, mightily powerful beast of a thing, and if you’ve ever had more fun in a car than you can have in one you probably did well not to be arrested for it.

One of the very greatest things about the RS is that it’s so outrageously powerful. So the RS Mountune FPM375 ought to be greater still, because it’s even more powerful.

Ford and Mountune are big mates, so the latter can mod away to its heart’s content and Ford won’t chuck its toys, and your warranty, out of the pram. In this case, the mods in question are upgrades to the ECU, air filter, dump valve and crossover duct.

You pay £899 for the privilege, and you get an extra 25bhp and 30lb ft. Hello 370bhp, hello 376lb ft.

What difference does this make? Normally, as good as none. Because normally, you’re not using all the car’s power, are you? That’s happy news, though, because as we all know tuning an engine can turn it into a thing that’s practically unusable at less than full throttle.

No such worries here. Instead, it waits patiently for the opportunity to show you what it can do – which happens when the open road (or track) beckons and you select Race mode.

Then… boom. The engine absolutely rages its way up through the revs, instantly reacting as the throttle goes down while making a noise that goads you into giving it more, more and then some more. Lift for an instant and the exhaust makes a noise like fireworks night in Oban (Google it…), goading you into giving it more, more and then some more, etc etc.

There’s no need to mess with the suspension for any of this, so the RS still handles like an RS should – no alarms, but plenty of hoots. It still rides like an RS should (or must), too, so your granny will take a taxi rather than asking for a lift. Choose for yourself whether this is a good or bad thing.

How much better is it? In percentage terms… who cares? In yee-ha terms, it’s more yee-ha than ever and that’s reason enough for any Focus RS buyer to call it a must-have. Awesome just got awesomer.